Characteristics and trend of distribution of rainfall in Singapore

• Main Author: Ong, Zhiwei.
• Other Authors: Tan Soon Keat
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Civil engineering::Water resources
• Online Access: http://hdl.handle.net/10356/15972
• Institution: Nanyang Technological University

In this report, time series analysis and student t-distribution hypothesis test are carried out to determine the rainfall trend pattern in Singapore and the confidence level of this rainfall trend occurring. The objective of this study is to analyze the characteristics and trend of distribution of rainfall in Singapore, and qualitatively evaluate how the trend going to impact on Singapore’s water resource quality. One hundred and thirty-three years of annual rainfall from the period 1875 to 2008 from MacRitchie rainfall station, were used in this study. Initially, the explanatory data analysis was used to plot several historical rainfall data graphs for different period of time (Northeast, Southwest monsoon, change period during the monsoons). The moving average technique proved to be a relevant method in removing the cyclic effect of annual rainfall time series. The series of annual rainfalls and their moving average values were analyzed using two approaches: trend of rainfall and the shift in rainfall quantities. The analyses were carried out using the time series analysis and student T-distribution test to obtain the confidence level for the observed trend. Implications on water resources quality attributable to the increasing rainfall trend were discussed. The finding indicates that a tendency beyond the variation expected from natural climatic cycles is happening. The study points to changing rainfall trend that we are currently experiencing, and the trend of these changes underlines the prediction that more intense rainfall could be expected in the South East Asia region.